Czochralski growth of mixed cubic sesquioxide crystals in the ternary system Lu2O3–Sc2O3–Y2O3

Cubic rare-earth sesquioxide crystals are strongly demanded host materials for high power lasers, but due to their high melting points investigations on their thermodynamics and the growth of large-size crystals of high optical quality remain a challenge. Detailed thermal investigations of the ternary system Lu 2 O 3 –Sc 2 O 3 –Y 2 O 3 revealing a large range of compositions with melting temperatures below 2200°C and a minimum of 2053°C for the composition (Sc 0.45 Y 0.55 ) 2 O 3 are presented. These reduced temperatures enable for the first time the growth of high optical quality mixed sesquioxide crystals with disordered structure by the conventional Czochralski method from iridium crucibles. An (Er 0.07 Sc 0.50 Y 0.43 ) 2 O 3 crystal is successfully grown and characterized with respect to its crystallographic properties as well as its composition, thermal conductivity and optical absorption in the 1 µm range.